Desert Introduction

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Introduction to hot deserts.

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  • Desert Introduction

    1. 1. White Sands National Monument, New Mexico, USA Wadi Dhar, Yemen Dead Vleii, Namib Desert DESERT INTRODUCTION
    2. 2. DISTRIBUTION OF DESERTS Annual precipitation in deserts is less than 250mm and less than 100mm in extreme deserts. Deserts have large diurnal temperature ranges.
    3. 8. Hot Desert Climates
    4. 10. Rock desert or hamada Sand desert or erg Stony desert
    5. 11. Basins of inland drainage called playas or shotts Dry ravines or wadis or arroyos Alluvial fans can join together to form a bajada
    6. 12. DESERT VEGETATION
    7. 13. This xerophytic or drought resistant vegetation has adapted to living in dry conditions by having small, twisted leaves with stomata which only open at night to allow respiration.
    8. 14. Perennials, such as ocotillo, become dormant between the rains. Once all moisture has evaporated from the soil, the plant drops its leaves and temporarily stops growing.
    9. 15. Instead of thorns, the creosote bush relies for protection on a smell and taste that wildlife find unpleasant. Creosote has an extensive double root system -- both radial and deep -- to accumulate water from both surface and ground water.
    10. 16. Cactus, xerophytic adaptations of the rose family, are among the most drought-resistant plants on the planet due to their absence of leaves, shallow root systems, ability to store water in their stems, spines for shade and waxy skin to seal in moisture.
    11. 17. Desert plants must act quickly when heat, moisture and light inform them it's time to bloom. Ephemerals are the sprinters of the plant world, sending flower stalks jetting out in a few days. The peak of this bloom may last for just days or many weeks, depending on the weather and difference in elevation.
    12. 18. WATER? IN THE DESERT?
    13. 19. RAINFALL
    14. 20. RAINFALL
    15. 21. RAINFALL
    16. 22. RIVER
    17. 23. RIVER
    18. 24. RIVER
    19. 25. RIVER
    20. 26. GROUNDWATER
    21. 27. GROUNDWATER
    22. 28. GROUNDWATER
    23. 29. Resources and Further Reading Robert G. Bailey (1998), Ecoregions, Springer-Verlag New York Farouk El-Baz et al.,(1982), The Desert Realm, National Geographic Tony Allan & Andrew Warren (1993), Deserts, Mitchell Beazley World Conservation Atlas www.geojuice.org

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